Drive belt tensioning apparatus

Abstract

A belt tensioning apparatus for tensioning a belt that extends between a driving shaft and driven shaft which are immovably supported with respect to one another. There is a flat spring, the free end of which bears against one run of the belt at a point between the two shafts. The opposite end of the spring is rigidly fixed so as to orient the spring within the plane of the belt such that the spring elastically deflects the belt run into a taut condition. A second leaf spring supported for cooperation with another belt run. Plural flat springs backing up the first mentioned springs for increasing the force applied thereby to the belt runs.

What is claimed is: 
     
       1. Apparatus for tensioning a drive belt that is trained around a driving sheave mounted on a first shaft and a driven sheave mounted on a second shaft supported substantially immovably in parallel spaced apart relation to said first shaft, said belt having a first and second belt run defined between said sheaves and disposed in spaced relation to each other, said apparatus comprising first and second elongate leaf springs each having a first end and a second end remote from said first end, and first and second spring mounting means for mounting said first end of each said spring substantially immovably with respect to said shafts, said first and second mounting means supporting an associated one of said springs to dispose said second end of said springs in rubbing contact with said belt on said first and second runs respectively and at a site intermediate said sheaves, said mounting means spporting said leaf springs to elastically deform an associated one of said springs and to deflect the belt on an associated one of said runs so as to tension the same, one of said sheaves being of a diameter smaller than the other said sheave and including an elongate rod mounted adjacent said smaller sheave, said elongate rod being spaced from said smaller sheave and being oriented substantially perpendicular to an imaginary line extending through said shafts, both said mounting means fixing the first ends of respective said springs at respective sites on said rod that are disposed on opposite sides of said smaller sheave. 
     
     
       2. Belt tensioning apparatus according to claim 1 wherein said elongate rod has a threaded portion thereon, wherein the first ends of said springs define holes sized to admit said rod therethrough and wherein said mounting means include nuts threadedly engaged with said rod and capturing the first ends of respective said springs. 
     
     
       3. Apparatus for tensioning a drive belt that is trained around a relatively small sheave mounted on a first shaft and a relatively large sheave mounted on a second shaft supported substantially immovably in parallel spaced apart relation to said first shaft, one of said sheaves being a driving sheave and one of said sheaves being a driven sheave, there being first and second belt runs between said sheaves, said apparatus comprising a threaded rod, means for rigidly mounting said threaded rod adjacent said small sheave and in spaced apart relation thereto at the side thereof opposite from said large sheave, first and second elongate leaf springs having first ends defining holes for receiving said threaded rod therethrough, a plurality of nuts threadedly engaged with said rod and retaining the first end of said first spring on one side of said small sheave and the first end of said second spring on the other side of said small sheave, said elongate springs having second ends remote from respective said first ends, said second ends extending substantially parallel to an imaginary line between said shafts and into rubbing contact with respective said belt runs at points intermediate said sheaves, the length of said springs and the position of said first ends as established by the position of said nuts being such as to elastically deform said springs and to deflect the belt on said runs inwardly so as to tension said belt.